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Old January 9th, 2006, 08:11 AM   #1
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difference between mic and line lvl.

Yup I am a newb to audio production, and just wanted to know the difference between mic and line level. Thanks
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Old January 9th, 2006, 08:55 AM   #2
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Quote:
Originally Posted by Sean Freeland
Yup I am a newb to audio production, and just wanted to know the difference between mic and line level. Thanks
The short of it is that mic levels are the very low voltage signals produced by, well, microphones. Line level signals are higher voltages such as the outputs of a preamp. If you were to connect a microphone to a set of powered computer speakers you probably would hear anything at all from them because the mic signal just wouldn't be strong enough to drive them. If you were to plug your IPOD's headphones out into them it would work just fine. OTOH, if you were to plug your IPOD headphones output into your soundcard's microphone input, it would be very loud and distorted as the signal from the IPOD would overload the mic input.
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Old January 9th, 2006, 09:01 AM   #3
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Mic signals are tiny voltage produced when the sound ways vibrate the mic diaphram. They range from about 1.5 millivolts in a dynamic mic to maybe 70 millivolts in a really hot (read: sensitive) mic (based on a reference sound pressure level). These signals are delicate and are easily corrupted by electrical noice. Line level signals are much stronger (higher voltage) and are basically an agreed upon industry standard of about 750 millivolts. Using line level signals enables various different devices from different manufactures to be interconnected. They also can be carrried over longer distances.


Mic signals are also characterized by their impedance, which affects how efficiently power (remember these are tiny delicate signals) is transferred from the mic source to an input of another device (usually a microphone preamp that raises the signal to "line" level). High quality mics have low impedances and are bests used when coupled to low impedenace inputs (low impedance means the current flowing is higher, and the signal therefore has greater noise immunity). Consumer mics often times have high impedenace (Hi-Z) and are coupled to Hi-Z imputs. Hi-Z signals are more readily affected by noise.
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Old January 9th, 2006, 11:06 AM   #4
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There's also two types of line level: consumer line level at -10dBV, and pro line level at +4dBu (or dBm). Note that these units are different.

The difference between the two is about 11.78dB.

RCA connectors usually are associated with -10dBV, XLR with +4dBu (or mic level), TRS quarter inch can be either.
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Old January 9th, 2006, 11:26 PM   #5
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sony lists their UWP wireless at -58dbm out...

would that be mic level????
Thanks
Mark
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Old January 10th, 2006, 06:34 AM   #6
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Originally Posted by Mark Slade
would that be mic level????
Thanks
Mark
Yes ... mic is in the range of -30 to -60. Line is from -10 to +4
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